Weegy: 2.Michael Collins was not on the ill-fated Apollo I User: program was to master the ability to work on the lunar surface.
Weegy: The answer is the Apollo program. User: What are some of the problems that needed to be overcome in order for NASA to be able to land men on the moon and return them safely?
Weegy: Scientific background
The primary concern of any moon landing is the high velocity involved that arises from the effects of gravity. In order to go to any moon, a spacecraft must first leave the gravity well of the Earth. [ The only practical way of accomplishing this currently is with a rocket. Unlike other airborne vehicles such as balloons or jets, only a rocket can continue to increase its speed at high altitudes in the vacuum outside the Earth's atmosphere.
Upon approach of the target moon, the spacecraft must decelerate enough to land safely. The velocity to be shed from the target moon's gravitational attraction is roughly equal to the escape velocity of the target moon. For Earth's Moon, this figure is 2.4 kilometers per second or around 6,000 miles per hour. This change in velocity (referred to as the delta-v) is usually provided by a landing rocket, which must be carried into space by the original launch vehicle as part of the overall spacecraft. An exception is a moon landing on Titan such as that carried out by the Huygens probe. As the only moon with an atmosphere, landings on Titan may be accomplished by using atmospheric entry techniques that are generally lighter in weight than a rocket with equivalent capability.
Whatever method is used to slow a spacecraft as it nears a moon, the key requirement for a "true" moon landing is to be traveling at a survivable speed upon reaching the moon's surface that allows continued operation after touchdown. Such landings may be characterized as "soft" if a human could survive them, and "hard" if only a ruggedized machine would do so. Initial American attempts at performing the first hard ... (More)